As part of a $30 million historic revitalization, Wiegmann Associates recently finished installing an updated HVAC system to the Soldiers Memorial Military Museum in downtown St. Louis, Missouri.

In order to preserve historical artifacts, the HVAC system was designed to maintain strict humidity levels, according to a release about the project:

A primary project challenge was developing an energy efficient HVAC system that reliably maintains comfortable temperature levels in spaces that are nearly empty at times and then fully occupied for events. Sensors control humidity and ventilation in each of 24 zones of the building, conditioning the inside air as needed depending on how the space is occupied.

The contractors paid close attention to aesthetic details to maintain the historic integrity of the nearly 80-year-old building. For example, Wiegmann installed low registers in the 28-foot tall galleries, with grills reflecting the art deco style of the building.

The museum opened in 1938 and is dedicated to soldiers killed in World War I. Upon the completion of the renovations, the museum will reopen on Nov. 3, 2018.